The present invention is related to an electric switch comprising a magnet and a reed contact which is actuatable by the magnetic force of the magnet.
One known type of electric switch is described in German patent specification No. 2,265,427. In this configuration, the reed contact is surrounded by the magnet which is fastened to the float. When the minimum liquid level is fallen short of, the electric switch is switched under the action of the magnetic force and gives a signal to a warning device which is connected to the electric switch. In such switch arrangements, the electric switch is frequently actuated incorrectly before the minimum liquid level is reached. The reasons for such erroneous triggering is that the amplitude of dispersion of the magnetic field is comparatively large and that the tolerances occurring during manufacture of the reed contact and of the magnet have a negative effect on the switching accuracy of the switch.
An object of the present invention is to provide an electric switch which switches exclusively when the magnet has assumed a determined position, independently of manufacturing tolerances and of the magnetic field.